From ffb00fbcbeeb2b0f17e70fbce81928e1f7fd4b46 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Fri, 7 Oct 2016 13:48:05 +0200
Subject: Modules: blocking commands WIP: API exported, a first example.

---
 src/module.c         | 23 +++++++++++++++++++++--
 src/modules/Makefile |  7 ++++++-
 src/redismodule.h    | 11 +++++++++++
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/module.c b/src/module.c
index 9a939d2fc..0cba99872 100644
--- a/src/module.c
+++ b/src/module.c
@@ -3085,7 +3085,21 @@ void unblockClientFromModule(client *c) {
     bc->client = NULL;
 }
 
-int RM_BlockClient(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback, RedisModuleCmdFunc timeout_callback, void (*free_privdata)(void*), long long timeout_ms) {
+/* Block a client in the context of a blocking command, returning an handle
+ * which will be used, later, in order to block the client with a call to
+ * RedisModule_UnblockClient(). The arguments specify callback functions
+ * and a timeout after which the client is unblocked.
+ *
+ * The callbacks are called in the following contexts:
+ *
+ * reply_callback:  called after a successful RedisModule_UnblockClient() call
+ *                  in order to reply to the client and unblock it.
+ * reply_timeout:   called when the timeout is reached in order to send an
+ *                  error to the client.
+ * free_privdata:   called in order to free the privata data that is passed
+ *                  by RedisModule_UnblockClient() call.
+ */
+RedisModuleBlockedClient *RM_BlockClient(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback, RedisModuleCmdFunc timeout_callback, void (*free_privdata)(void*), long long timeout_ms) {
     client *c = ctx->client;
     c->bpop.module_blocked_handle = zmalloc(sizeof(RedisModuleBlockedClient));
     RedisModuleBlockedClient *bc = c->bpop.module_blocked_handle;
@@ -3099,7 +3113,7 @@ int RM_BlockClient(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback, Redis
     c->bpop.timeout = timeout_ms;
 
     blockClient(c,BLOCKED_MODULE);
-    return REDISMODULE_OK;
+    return bc;
 }
 
 /* Unblock a client blocked by `RedisModule_BlockedClient`. This will trigger
@@ -3513,4 +3527,9 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(RetainString);
     REGISTER_API(StringCompare);
     REGISTER_API(GetContextFromIO);
+    REGISTER_API(BlockClient);
+    REGISTER_API(UnblockClient);
+    REGISTER_API(IsBlockedReplyRequest);
+    REGISTER_API(IsBlockedTimeoutRequest);
+    REGISTER_API(GetBlockedClientPrivateData);
 }
diff --git a/src/modules/Makefile b/src/modules/Makefile
index 1027b2e0e..066e65e9b 100644
--- a/src/modules/Makefile
+++ b/src/modules/Makefile
@@ -13,7 +13,7 @@ endif
 
 .SUFFIXES: .c .so .xo .o
 
-all: helloworld.so hellotype.so testmodule.so
+all: helloworld.so hellotype.so helloblock.so testmodule.so
 
 .c.xo:
 	$(CC) -I. $(CFLAGS) $(SHOBJ_CFLAGS) -fPIC -c $< -o $@
@@ -28,6 +28,11 @@ hellotype.xo: ../redismodule.h
 hellotype.so: hellotype.xo
 	$(LD) -o $@ $< $(SHOBJ_LDFLAGS) $(LIBS) -lc
 
+helloblock.xo: ../redismodule.h
+
+helloblock.so: helloblock.xo
+	$(LD) -o $@ $< $(SHOBJ_LDFLAGS) $(LIBS) -lpthread -lc
+
 testmodule.xo: ../redismodule.h
 
 testmodule.so: testmodule.xo
diff --git a/src/redismodule.h b/src/redismodule.h
index 4743fa98c..e931ecd07 100644
--- a/src/redismodule.h
+++ b/src/redismodule.h
@@ -84,6 +84,7 @@ typedef struct RedisModuleCallReply RedisModuleCallReply;
 typedef struct RedisModuleIO RedisModuleIO;
 typedef struct RedisModuleType RedisModuleType;
 typedef struct RedisModuleDigest RedisModuleDigest;
+typedef struct RedisModuleBlockedClient RedisModuleBlockedClient;
 
 typedef int (*RedisModuleCmdFunc) (RedisModuleCtx *ctx, RedisModuleString **argv, int argc);
 
@@ -194,6 +195,11 @@ int REDISMODULE_API_FUNC(RedisModule_StringAppendBuffer)(RedisModuleCtx *ctx, Re
 void REDISMODULE_API_FUNC(RedisModule_RetainString)(RedisModuleCtx *ctx, RedisModuleString *str);
 int REDISMODULE_API_FUNC(RedisModule_StringCompare)(RedisModuleString *a, RedisModuleString *b);
 RedisModuleCtx *REDISMODULE_API_FUNC(RedisModule_GetContextFromIO)(RedisModuleIO *io);
+RedisModuleBlockedClient *REDISMODULE_API_FUNC(RedisModule_BlockClient)(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback, RedisModuleCmdFunc timeout_callback, void (*free_privdata)(void*), long long timeout_ms);
+int REDISMODULE_API_FUNC(RedisModule_UnblockClient)(RedisModuleBlockedClient *bc, void *privdata);
+int REDISMODULE_API_FUNC(RedisModule_IsBlockedReplyRequest)(RedisModuleCtx *ctx);
+int REDISMODULE_API_FUNC(RedisModule_IsBlockedTimeoutRequest)(RedisModuleCtx *ctx);
+void *REDISMODULE_API_FUNC(RedisModule_GetBlockedClientPrivateData)(RedisModuleCtx *ctx);
 
 /* This is included inline inside each Redis module. */
 static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int apiver) __attribute__((unused));
@@ -295,6 +301,11 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(RetainString);
     REDISMODULE_GET_API(StringCompare);
     REDISMODULE_GET_API(GetContextFromIO);
+    REDISMODULE_GET_API(BlockClient);
+    REDISMODULE_GET_API(UnblockClient);
+    REDISMODULE_GET_API(IsBlockedReplyRequest);
+    REDISMODULE_GET_API(IsBlockedTimeoutRequest);
+    REDISMODULE_GET_API(GetBlockedClientPrivateData);
 
     RedisModule_SetModuleAttribs(ctx,name,ver,apiver);
     return REDISMODULE_OK;
-- 
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